You have advantage on Dexterity (Stealth) checks made to move silently.
If you take the Hide action while not wearing armor, you can roll a Stealth check even if you’re only lightly obscured, provided you made no sound that turn.

Your alien blood gives you heightened awareness of sound — both its presence and absence.

• You are blind, but you possess Echolocation out to 60 feet.

• You cannot see anything beyond that range, even with magical light.

• You automatically detect any creature that makes noise within your echolocation radius, even through walls or cover (as long as sound can travel).

If you are ever deafened, you are effectively blinded until the condition ends.

Your physiology is built for rapid, explosive movement.

• Your base movement speed increases to 35 feet.

• You have advantage on Dexterity (Acrobatics) checks.

• You can climb difficult surfaces (including ceilings) without needing to make an ability check.

As a bonus action, you can focus your echolocation on a single point within 60 feet. For the next minute, you gain precise awareness of all creatures that make noise within 30 feet of that point (no Stealth checks against you unless magically silenced).

You can use this feature a number of times equal to your proficiency bonus, regaining all expended uses when you finish a long rest.

Your chitinous hide is like living armor.
While unarmored, your AC equals 13 + your Dexterity modifier.

At level 5, this increases to 14 + your Dexterity modifier, as your plating hardens.

Your hypersensitive hearing can be turned against you.
When you take thunder damage, you must succeed on a Constitution saving throw (DC = 10 or half the damage taken, whichever is higher) or become stunned until the end of your next turn.